Hydraulic Cushioning Device and Cushioning Cylinder Comprising Device

ABSTRACT

A hydraulic buffer pertains to the field of hydraulic parts. A signal device (X) is installed at a position close to an end of a cylinder stroke to control movement of slide valves ( 12, 18, 12   a,    12   b,    12   c,    12   d,    12   e,    12   f, F   1 , F 2 , F 3 , F 4 ) of the hydraulic buffer, to dynamically adjust the degree of valve openness and a liquid flow direction of a buffering module (Y), and therefore control pressure of oil entering an oil returning chamber of a cylinder. The high-pressure chamber of the cylinder releases pressure and unloads, and/or the oil returning chamber throttles to load pressure, such that a moving speed of a cylinder piston ( 6 ) at the end of the stroke is controlled, realizing buffering of the cylinder. The device eliminates defects in the prior art in which a buffering mechanism of a cylinder is complex, manufacturing accuracy requirements are high, structural arrangement is difficult, it is difficult to employ a combined configuration in which an oil returning chamber throttles to load pressure and a high-pressure chamber releases pressure and unloads, and buffering efficiency is not high. The device has desirable buffering controllability and high reliability, such that the overall quality is improved.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a hydraulic assembly, and more particularly to a hydraulic cushioning device and a cushioning cylinder connected with the hydraulic cushioning device of an engineering apparatus.

2. Description of Related Art

For cycling operations of engineering apparatuses such as digging operation of an excavator or shoveling operation of a bulldozer, a conventional cushioning cylinder is a key system to the engineering apparatuses. The conventional cushioning cylinder may utilize a piston rod to process a dynamic operation, and may be applied with a conventional cushion to provide a cushioning effect to the engineering apparatus.

However, the conventional cushioning cylinder connected with the conventional cushion has the following shortcomings.

1. The method of the conventional cushion to provide a cushioning effect is monotonous, and a structural arrangement is complicated.

2. Difficulties in combining two kinds of cushioning methods, i.e., throttling backpressure of a return chamber and pressure-relief unloading of a pressure chamber, cause low cushioning efficiency.

3. A cushioning process due to throttling backpressure is unable to self-adjust against moving velocity of the piston rod since a throttling opening of the conventional cushioning cylinder is fixed. Therefore, the cushioning effect is poor in controllability and quality.

4. Low reliability. Manufacturing precision is highly required for a conventional cushioning cylinder. The cushioning effect may fail due to a small defect or eccentricity on part of assemblies of the conventional cushioning cylinder and the connected cushioning device.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a hydraulic cushioning device and a cushioning cylinder combined with the hydraulic cushioning device. The present invention is good at cushioning, safe, and reliable, so the shortcomings of the conventional cushioning cylinder and the conventional cushion may be overcome.

A hydraulic cushioning device is connected with a cushioning cylinder that is controlled and cushioned by the hydraulic cushioning device. The hydraulic cushioning device comprises at least one signal generator and a cushioning module. The at least one signal generator is disposed in a chamber of the cushioning cylinder and has a signal chamber and a signal plug. The signal chamber is disposed on a top end or a bottom end of the cushioning cylinder. The signal plug is able to slide relative to the signal chamber and protrudes on a side of a piston assembly of the cushioning cylinder. The cushioning module is integrally formed on or assembled to the cushioning cylinder, and has a valve body, at least one slide valve, and at least one elastic component. The at least one slide valve is each respectively connected to the at least one signal generator, is controlled by the at least one generator to adjust the hydraulic flow passing into and out of the cushioning cylinder, and has a damping hole disposed therethrough. The at least one elastic component is mounted in the valve body and abuts the valve body and the at least one slide valve. The signal plug moving with the piston assembly selectively enters and slides in the signal chamber.

Because the signal chamber is then independent from the chamber of the cushioning cylinder, oil may be thereby sent from the signal chamber with part of the oil flowing through the damping hole and the rest of the oil that is sent from the signal chamber pushing the at least one slide valve to move against the at least one elastic component. By this process, the hydraulic flow passing into and out of the cushioning cylinder may be adjusted and cushioned by methods of pressure-relief unloading of a pressure chamber and/or throttling backpressure of a return chamber.

Besides, the hydraulic cushioning device further has at least one check valve. The at least one check valve is connected between an opening of the valve body and the signal chamber so that hydraulic flow may unidirectionally flow from the opening.

A cushioning cylinder with the hydraulic cushioning device as mentioned above is also provided. The cushioning cylinder has a cylinder body and a piston assembly. The cylinder body has a top end and a bottom end. The piston assembly slidably moves in the cylinder body and has a piston rod and a piston. The piston is mounted with the piston rod and divides a space inside the cylinder body into a first chamber and a second chamber. The cushioning module of the hydraulic cushioning device is integrally formed on or assembled to the cushioning cylinder, the at least one signal generator is disposed in the first chamber or the second chamber, and the at least one signal generator is able to control movement of the at least one slide valve of the cushioning module to cushion the piston by pressure-relief unloading of a pressure chamber and throttling backpressure of a return chamber.

Moreover, the cushioning module has two slide valves, and the two slide valves are each integrally formed on or assembled to the bottom end and the top end of the cushioning cylinder.

In addition, the signal plug is formed as a single piece on the piston assembly, or is manufactured from a wear-resistant or elastic material and mounted to the piston assembly.

With respect to the conventional hydraulic system, the present invention has the following advantages:

1. A cushioning resistance and a velocity of the piston are mutually responsive, so the cushioning effect is controllable and self-adjustable, which means the cushioning effect has high quality and stability.

2. The signal generator makes the cushioning module have a simplified structure. Also, components of the cushioning module are unlikely to affect the cushioning effect due to defects or eccentricity. Therefore, the cushioning module may have a longer lifetime and a higher reliability.

3. The quality of the cushioning effect improves so that strokes will not harm the cushioning cylinder anymore. The cushioning cylinder also may have a longer lifetime.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in partial section of a first embodiment of a hydraulic cushioning device and a cylinder combined with the hydraulic cushioning device in accordance with the present invention;

FIG. 2A is a side view in partial section of a beginning status of the hydraulic system in FIG. 1;

FIG. 2B is a side view in partial section of a processing status of the hydraulic system in FIG. 1;

FIG. 3 shows a movement in an opposite direction of the hydraulic system in FIG. 1;

FIG. 4 is a side view in partial section of a substitute structure of the hydraulic system in FIG. 1, wherein the slide valves are substituted with first valve cores;

FIG. 5 is a side view in partial section of the hydraulic system in FIG. 1 equipped with check valves, so fast oil-filling is practicable;

FIG. 6 is a side view in partial section of the hydraulic system in FIG. 4 equipped with check valves, so fast oil-filling is practicable;

FIG. 7 is a side view in partial section of another substitute structure of the hydraulic system in FIG. 1 equipped with combined valves;

FIGS. 8A to 8D are enlarged side views in partial section of the combined valves in FIG. 7, with respect to four configurations of the combined valves;

FIG. 9 is a side view in partial section of a second embodiment of a hydraulic cushioning device and a cylinder combined with the hydraulic cushioning device in accordance with the present invention;

FIG. 10 is a side view in partial section of a substitute structure of the hydraulic system in FIG. 9, wherein the slide valve is substituted with the first valve core;

FIG. 11 is a side view in partial section of another substitute structure of the hydraulic system in FIG. 9, wherein the slide valve is substituted with a second valve core;

FIG. 12 is a side view in partial section of another substitute structure of the hydraulic system in FIG. 11, wherein the second valve core is substituted with a third valve core;

FIG. 13 is a side view in partial section of a further substitute structure of the hydraulic system in FIG. 9 equipped with check valves, so fast oil-filling is practicable;

FIG. 14 is a side view in partial section of a third embodiment of a hydraulic cushioning device and a cylinder with the hydraulic cushioning device combined in accordance with the present invention;

FIG. 15 is a side view in partial section of a substitute structure of the hydraulic system in FIG. 14, wherein the valve core is substituted with a valve core;

FIG. 16 is a side view in partial section of another substitute structure of the hydraulic system in FIG. 14, wherein the valve core is substituted with a valve core;

FIG. 17 is a side view in partial section of the second plug that has moved into the second signal chamber of the hydraulic system in FIG. 16, and shows that the hydraulic cushioning device is working;

FIG. 18 is a side view in partial section of a further substitute structure of the hydraulic system in FIG. 14 equipped with check valves, so fast oil-filling is practicable;

FIG. 19 is a side view in partial section of a fourth embodiment of a hydraulic cushioning device and a cylinder combined in accordance with the present invention, and the slide valve is utilized;

FIG. 20 is a side view in partial section of a substitute structure of the hydraulic system in FIG. 19, wherein the slide valve is substituted with the first valve core;

FIG. 21 is a side view in partial section of another substitute structure of the hydraulic system in FIG. 19 equipped with check valves, so fast oil-filling is practicable;

FIG. 22 is a side view in partial section of a fifth embodiment of a hydraulic cushioning device and a cylinder combined in accordance with the present invention;

FIGS. 23 to 25 show three substitute structures which replace the slide valve with the first valve core, the second valve core, and the third valve core; and

FIG. 26 is a side view in partial section of a further substitute structure of the hydraulic system in FIG. 22 equipped with check valves, so fast oil-filling is practicable.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Detailed descriptions of embodiments of the present invention are supported with the drawings and shown as follows.

First Embodiment

With reference to FIGS. 1 to 3, a hydraulic cushioning device and a cushioning cylinder combined with the hydraulic cushioning device in accordance with the present invention comprise two signal generators X, a cushioning module Y, and the cushioning cylinder Z. The three components are connected by oil lines. Adopting two methods of cushioning, i.e., pressure-relief unloading of a pressure chamber and throttling backpressure of a return chamber, a velocity of a piston of the hydraulic system may be adjusted at the end of a process. Bidirectional cushioning effect may be accomplished as well. In the drawings, flow directions are indicated by arrows. The cushioning cylinder Z has a cylinder body 2, a piston rod 4, a piston 6, a top end B, and a bottom end A. The piston 6 and the piston rod 4 are connected as a piston assembly sliding in the cylinder body 2, and the piston 6 divides the space inside the cylinder body 2 into a first chamber 3 and a second chamber 8. The cushioning module Y has a valve body 10, two slide valves 12, 18, and two elastic components 30.

The valve body 10 comprises two sets of major and minor holes, including a first major hole 15, a second major hole 31, a first minor hole 34, and a second minor hole 19. The first major hole 15 has a first major oil groove 36 and a first minor oil groove 11, which are radially disposed in the first major hole 15 and spaced from each other in an axial direction. The second major hole 31 has a second major oil groove 24 and a second minor oil groove 27, which are radially disposed in the second major hole 31 and spaced from each other in an axial direction. Moreover, the first minor oil groove 11 communicates with the second major oil groove 24 through a first channel 26, and the first major oil groove 36 communicates with the second minor oil groove 27 through a second channel 33.

Besides, the valve body 10 further comprises a first outer opening 14, a second outer opening 32, a first side opening 37, and a second side opening 25. The first outer opening 14 and the second outer opening 32 coaxially communicate with the first major hole 15 and the second major hole 31, and are connected with oil lines of the hydraulic system, respectively. The first side opening 37 and the second side opening 25 communicate with the first major hole 15 and the second major hole 31, and are connected to the first chamber 3 and the second chamber 8 of the cushioning cylinder Z via oil lines, respectively. The two signal chambers 1, 9 of the two signal generators X are respectively connected to the first side opening 34 and the second side opening 19 to control the corresponding slide valves 12, 18. The two slide valves 12, 18 are a first slide valve 12 and a second slide valve 18, and are slidably mounted in the first major hole 15 and the second major hole 31, respectively.

Each one of the two slide valves 12, 18 has a valve surface 28, a cavity 29, an auxiliary surface 21, a damping hole 20, a main oil hole 23, multiple supplementary oil holes 22, and a shoulder portion 42. The valve surface 28 and the auxiliary surface 21 are located on two different ends of the slide valves 12, 18. The damping hole 20 is disposed through a center of the slide valves 12, 18, and communicates with the cavity 29 and a main oil chamber 13 of the slide valves 12, 18. The cavity 29 is disposed through the valve surface 28 to the main oil hole 23 that is radially disposed through the slide valves 12, 18. The valve surface 28 is fit in the two major holes 15, 31. The auxiliary surface 21 is fit in the two minor holes 19, 34. An outer diameter of the auxiliary surface 21 is smaller than an outer diameter of the valve surface 28.

The shoulder portion 42 is located between a part with the outer diameter of the auxiliary surface 21 and a part with the outer diameter of the valve surface 28. The supplementary holes 22 are axially disposed through the shoulder portion 42, and communicate with the cavity 29 and a respective auxiliary oil chamber 40, 41. The two elastic components 30 are mounted in the cavity 29 of the slide valves 12, 18 and the two outer openings 14, 32, and the corresponding shoulder portions 42 thereby abut the two major holes 15, 31. The two signal generators X are respectively disposed in the first chamber 3 and the second chamber 8, and are connected to the respective slide valves through oil lines 16, 35. The two signal generators X are composed of two signal chambers 1, 9 and two signal plugs 5, 7, wherein the two signal chambers 1, 9 are respectively disposed on the top end B and the bottom end A of the cushioning cylinder Z.

The two signal plugs 5, 7 protrude on the two sides of the piston 6, and slidably align with the signal chambers 1, 9. With reference to FIGS. 1 and 2A, the valve surface 28 of the slide valves 12, 18 keeps fit with the corresponding major holes 15, 31, and the main oil hole 23 aligns with the corresponding major oil grooves 24, 36. Openings communicating between the radial main oil hole 23 and the major oil groove 24, 36 are maximized. In addition, at the same time, the minor oil grooves 11, 27 are covered and blocked by the valve surfaces 28, so the minor oil grooves 11, 27 are blocked from communicating with the cavities 29 of the slide valves 12, 18. As the slide valves 12, 18 move toward the other end, the main oil holes 23 will gradually depart from the major oil grooves 24, 36 to the minor oil grooves 11, 27.

After the movement, the minor oil grooves 11, 27 will communicate with the main oil holes 23, and the major oil grooves 24, 36 will be blocked by the valve surface 28 and communication between them is thereby blocked. The two slide valves 12, 18 may slide axially according to control signals from the corresponding signal generators X so as to adjust amount and flowing direction of oil. Consequently, the methods of throttling backpressure of a return chamber and pressure-relief unloading of a pressure chamber may be utilized at the same time and provide a cushioning effect.

Detailed description of how the cushioning works is as follows.

The hydraulic system comprises the signal generators X and the cushioning module Y. The two signal generators X are mounted in the first chamber 3 and the second chamber 8 of the cushioning cylinder Z. The first signal chamber 1 and the second signal chamber 9 of the two signal generators X are respectively disposed on the top end B and the bottom end A, and slidably align with the first signal plug 5 and the second signal plug 7 that protrude on the two sides of the piston 6, respectively. Compressed oil coming from the relative movements will serve as a control signal, and make the slide valves 12, 18 of the cushioning module Y able to slide under control. In this way, the cushioning effect on the piston 6 of the cushioning cylinder Z is adjustable.

When the piston 6 keeps still or moves before the first signal plug 5 enters the first signal chamber 1 (or before the second signal plug 7 enters the second signal chamber 9), with reference to FIGS. 1 and 2A, the shoulder portions 42 of the first slide valve 12 and the second slide valve 18 are pushed by the two elastic components 30 and thus abut the major holes 15, 31. Synchronically, the main oil holes 23 of the first slide valve 12 and the second slide valve 18 align with the first major oil groove 36 and the second major oil groove 24, respectively. Multiple valve openings 39 between the main oil holes 23 and the two major oil grooves 36, 24 are maximized consequently. That is to say, the main oil holes 23 of the first and the second slide valves 12, 18 remain in full communication with the major oil grooves 36, 24. No control signal is sent from the signal generators X then, so the cushioning module Y cannot be actuated and provide a cushioning effect.

With reference to FIG. 2A, the piston 6 is moved from the first chamber 3 to the second chamber 8, and the second signal plug 7 has not entered the second signal chamber 9. Compressed oil flows into the first chamber 3 through the first outer opening 14, the main oil chamber 13 of the first major hole 15, the cavity 29 and the main oil hole 23 of the first slide valve 12, the first major oil groove 36, the first side opening 37, and a first cylinder oil line 38. (A little of the compressed oil flows into the first chamber 3 through the damping hole 20 of the first slide valve 12 and a first oil line 35.) The compressed oil flowing into the first chamber 3 pushes the piston 6 toward the second chamber 8. Furthermore, oil in the second chamber 8 starts to be compressed by the piston 6 and flows to an oil tank W via a second cylinder oil line 17, the second side opening 25, the second major oil groove 24, the main oil hole 23 and the cavity 29 of the second slide valve 18, and the main oil chamber 13 and the second outer opening 32. (A little of the compressed oil flows to the oil tank W via a second oil line 16 and the damping hole 20 of the second slide valve 18.)

Because the first and the second minor oil grooves 11, 27 are respectively blocked by the valve surfaces 28 of the first and the second slide valves 12, 18, the first minor oil groove 11 is unable to communicate with the cavity 29 of the first slide valve 12, and the second minor oil groove 27 is unable to communicate with the cavity 29 of the second slide valve 18. Therefore, the oil flows independently in the two major holes 15, 31, respectively pressure oil and return oil for the cushioning cylinder Z, and collaboratively drives the piston 6 of the cushioning cylinder Z to work as a conventional cushioning cylinder. For the time being, the first chamber 3 is a pressure chamber, and the second chamber 8 is a return chamber.

When the piston 6 keeps moving to a position shown by imaginary lines in FIG. 2A and the second signal plug 7 enters the second signal chamber 9, the second signal plug 7 isolates the second signal chamber 9 from the second chamber 8. Assume that V0 is a velocity of the piston 6, and P3, P8, and P9 are respectively values of hydraulic pressure of the first chamber 3, the second chamber 8, and the second signal chamber 9. A value of hydraulic pressure of the second minor hole 19 is also P9. At present, P3 shall be the working pressure of the cushioning cylinder Z. P8 and P9 are the oil-returning pressure of the oil tank W, being zero under assumption of no pressure loss. With reference to FIG. 2B, as the piston 6 keeps moving, a volume of the second signal chamber 9 begins to reduce, so P9 becomes larger and drives the oil to flow to the second minor hole 19 of the cushioning module Y as a control signal. Other than a little portion of the oil flowing through the damping hole 20 of the second slide valve 18 to the oil tank W, the rest of the oil will force the second slide valve 18 to slide in the second major hole 31 against restoring effect of the elastic component 30.

The valve opening 39 between the main oil hole 23 of the second slide valve 18 and the second major oil groove 24 narrows and causes throttling, so a resistance against returning oil promotes P8 to rise and may slow down the piston 6. On the other hand, the main oil hole 23 of the second slide valve 18 gradually communicates with the second minor oil groove 27, so the compressed oil may flow to the oil tank W via the main oil hole 23 of the first slide valve 12, the first major oil groove 36, the second channel 33, the second minor oil groove 27, the main oil hole 23 and the cavity 29 of the second slide valve 18. Therefore, the hydraulic system may start to unload, P3 in the first chamber 3 decreases, so V0 of the piston 6 decreases due to collaboration of loss of a pushing force and a gain of resisting force.

Next, the second signal plug 7 slows down in the second signal chamber 9 as V0 decreases, so P9 will become smaller, which means the pressing force against the second slide valve 18 will decrease. The second slide valve 18 will slide accordingly to variation of P9 and the restoring force of the elastic component 30. Cushioning effect of the hydraulic system may be thereby raised in quality since V0 and the valve openings 39 have a negative correlation. Larger V0 of the piston 6 drives more oil to the second minor hole 19 from the signal generator X on the bottom end A of the cushioning cylinder Z, and leads to a larger displacement of the second slide valve 18 and a smaller valve opening 39. The smaller valve opening 39 leads to a larger throttling resistance, and thus P8 will increase and slow down the piston 6. Throughout the cushioning process, V0 is at a maximum at the beginning, and the valve opening 39 tends to shrink the fastest to acquire the largest oil-returning resistance.

As V0 gradually decreases, the valve opening 39 will expand to lower the resistance. When V0 has decreased to a critical value V1, the oil as the control signal from the second signal chamber 9 may be completely exhausted through the damping hole 20, and no more oil may push the second slide valve 18. Then, the second slide valve 18 will reach a stable equilibrium by collaborations of P3, P8, P9, and the restoring force of the elastic component 30, and the piston 6 may stably finish a stroke with velocity of V1. After the piston 6 reaches the bottom end A of the cushioning cylinder Z, the second slide valve 18 will be pushed back to an original position by the elastic component 30. Oil may fill a second auxiliary oil chamber 40 through the supplementary holes 22 of the second slide valve 18, when the second slide valve 18 moves.

The critical value V1 of the velocity of the piston 6 may represent the quality of the cushioning effect. A smaller V1 means a smaller colliding force when a stroke is finished, i.e., a better quality of the cushioning effect. Moreover, the critical value V1 is influenced by factors including coefficients of elasticity of the elastic components 30, pre-loaded pressure to the elastic components 30, diameters of the damping holes 20, surface areas of the signal chambers 1, 9, and surface areas of the minor holes 34, 19. A manufacturer may set up a critical value V1 by adjusting these factors. Theoretically, the critical value V1 may be adjusted to nearly zero.

Sensitivity of the cushioning may be raised by increasing a ratio of the surface areas between the signal chambers 1, 9 and the corresponding minor holes 34, 19, decreasing the diameters of the damping holes 20, using elastic components 30 with smaller coefficients of elasticity, or reducing pre-loaded pressure to the elastic components 30. Also, an effective backpressure area of the return chamber may be increased by decreasing the surface areas of the signal chambers 1, 9.

The foregoing paragraphs described the cushioning effect that occurs in the process that the piston 6 of the cushioning cylinder Z moves from the first chamber 3 toward the second chamber 8. During this process, the signal generator X, which communicates with the second chamber 8, works and controls the second slide valve 18 to finish the cushioning process. With reference to FIG. 3, when the piston 6 moves reversely from the second chamber 8 toward the first chamber 3, it turns to the signal generator X which communicates with the first chamber 3 to work and control the first slide valve 12 to finish the cushioning process. Detailed description of the cushioning process is under the same working principle with the cushioning process mentioned above.

Furthermore, with reference to FIG. 4, the two slide valves 12, 18 in FIGS. 1 to 3 may be equivalently substituted with two valve cores 12A. The auxiliary surfaces 21 and the supplementary oil holes 22 of the slide valves 12, 18 are removed from the valve cores 12A. A mechanism for the cushioning module Y with the valve cores 12A remains the same as the cushioning module Y with the slide valves 12, 18, so detailed description thereof will be omitted.

With reference to FIGS. 5 and 6, check valves 43 are selectively mounted between the first outer opening 14 and the first signal chamber 1 or between the second outer opening 32 and the second signal chamber 9 as shown in FIGS. 1 to 4, so oil may flow in one way from the outer openings 14, 32 to the signal chambers 1, 9. With the check valves 43, the signal chambers 1, 9 of the signal generators X may be instantly refilled with oil, in case that oil being throttled at the damping holes 20 cannot flow into the signal chambers 1, 9 in time when the piston 6 moves reversely.

Additionally, a series of combined valves F may be obtained by revising the first and the second slide valves 12, 18 and the valve cores 12A. The combined valves F are also equipped with functions of the check valves 43. Therefore, with reference to FIG. 7, the slide valves 12, 18, and the check valves 43 may be replaced by the combined valves F. With reference to FIGS. 7 and 8A to 8D, the combined valves F comprise a first combined valve F1, a second combined valve F2, a third combined valve F3, and a fourth combined valve F4 with respect to FIGS. 8A to 8D. Each one of the combined valves F has a valve sleeve and a check-valve rod. The valve sleeve preserves the characteristics of the cavities 29 and the valve surfaces 28 of the slide valves 12, 18, yet the auxiliary surfaces 21 are removed.

Besides, the valve sleeve has a linear guiding hole 50 or a conical guiding hole 50A, and a sunk hole 47. The linear guiding hole 50 and the conical guiding hole 50A are enlarged from the damping holes 20. The sunk hole 47 is axially disposed on the shoulder portion 42 of each one of the combined valves F. In addition, the sunk hole 47 selectively has the supplementary oil holes 22 communicating with it. According to these technical features, the valve sleeve has three configurations: a first valve sleeve 18A, a second valve sleeve 18B, and a third valve sleeve 18C. The first valve sleeve 18A has the linear guiding hole 50 and the sunk hole 47 with the supplementary oil holes 22. The second valve sleeve 18B has the linear guiding hole 50 and the sunk hole 47 without the supplementary oil holes 22. The third valve sleeve 18C has the conical guiding hole 50A and the sunk hole with the supplementary oil holes 22. The check-valve rod has four configurations: a first check-valve rod 21A, a second check-valve rod 21B, a third check-valve rod 21C, and a fourth check-valve rod 21D. The combined valves F1, F2, F3, F4 are combined from the three configurations of the valve sleeves 18A, 18B, 18C and the four configurations of the check-valve rod 21A, 21B, 21C, 21D.

With reference to FIG. 8A, the first combined valve F1 comprises a first valve sleeve 18A, a check-valve rod 21A, and an elastomer 46. The first check-valve rod 21A has a cylindrical body, a protrusion 49, a damping hole 20, a fast-filling channel 48, and multiple fast-filling holes 45. The cylindrical body comprises a guiding portion 44 and a piston portion 19B, which are respectively located on two different sides of the protrusion 49. The guiding portion 44 slides in the linear guiding hole 50 of the first valve sleeve 18A. The piston portion 19B slides in the second minor hole 19 of the valve body 10. The damping hole 20 and the fast-filling channel 48 are disposed different ends through a center of the first check-valve rod 21A. The fast-filling holes 45 are radially disposed through the cylindrical body and communicate with the fast-filling channel 48 near the damping hole 20.

The elastomer 46 is pre-pressed and covers the piston portion 19B, with one end abutting the protrusion 49 and the other end abutting an interior surface at an end of the second minor hole 19. The protrusion 49 is therefore pressed and abuts a bottom of the sunk hole 47 of the first valve sleeve 18A. In order to coordinate the first combined valve F1, the valve body 10 further has a fast-filling groove 19A. The fast-filling groove 19A is disposed at an exterior end of the second minor hole 19, and extends in a radial direction. Besides, the fast-filling groove 19A is connected to one of the signal generators X via oil lines. Generally, the fast-filling holes 45 are located in the second minor hole 19, thereby blocking the communication to the fast-filling groove 19A. The oil in the fast-filling channel may only flow to the fast-filling groove 19A through the damping hole 20 as in a closed status. When the check-valve rod 21A moves toward the fast-filling groove 19A, the fast-filling hole 45 will gradually communicate with the fast-filling groove 19A. The oil in the fast-filling channel 48 may flow into the corresponding signal chamber 1, 9 of the signal generator X through the fast-filling hole 45 and the fast-filling groove 19A, as in an open status. The elastomer 46 may be a wire spring, a flat spring, or an elastic rubber, etc. that may restore the check-valve rod 21A.

Second Embodiment

With reference to FIGS. 9 to 13, a second embodiment of the hydraulic cushioning device has two signal generators X and a cushioning module Y. The cushioning module Y has two slide valves 12, 18 respectively connected to the two signal generators X. The two signal generators X are disposed in a first chamber 3 and a second chamber 8 of a cushioning cylinder Z, and are connected to the two slide valves 12, 18, respectively, via oil lines 16, 35. By throttling backpressure of a return chamber, a moving velocity of a piston of the cushioning cylinder Z may be controlled, and a bidirectional cushioning effect may be achieved. The second embodiment differs from the first embodiment in that: only the two major oil grooves 24, 36 of the two major holes 15, 31 are preserved. The two minor oil grooves 11, 27 and the two channels 26, 33 are omitted. The slide valves 12, 18 may also be replaced with three configurations of valve cores 12A, 12B, 12C. A first valve core 12A only omits the auxiliary surface 21 and the supplementary oil holes 22 from the slide valves 12, 18. A second valve core 12B removes the main oil holes 23 from the slide valves 12, 18. A third valve core 12C removes the auxiliary surface 21, the supplementary oil holes 22, and the main oil holes 23 from the slide valves 12, 18. Other technical characteristics are the same as the method of throttling backpressure of a return chamber of the first embodiment. With reference to FIG. 13, similar to the first embodiment, the check valves 43 are selectively mounted between the two outer openings 14, 32 and the corresponding signal chambers 1, 9. Therefore, the signal chambers 1, 9 may be instantly refilled with oil through the check valves 43.

Third Embodiment

With reference to FIGS. 14 to 18, a third embodiment of the hydraulic cushioning device has two signal generators X and a cushioning module Y. The cushioning module Y has two slide valves 12, 18 respectively connected to the two signal generators X. The two signal generators X are disposed in a first chamber 3 and a second chamber 8 of a cushioning cylinder Z, respectively, and are each connected to a respective one of the two slide valves 12, 18 via the oil lines 16, 35. By pressure-relief unloading of a pressure chamber, a moving velocity of a piston of the cushioning cylinder Z may be controlled, and a bidirectional cushioning effect may be achieved. In comparison with the first embodiment of the present invention, the slide valves 12, 18 are respectively replaced with a fourth valve core 12D, a fifth valve core 12E, and a sixth valve core 12F. Also, connection of oil lines differs in that the two signal chambers 1, 9 are respectively connected with the minor holes 34, 19 by the oil lines 16, 35. Other technical characteristics are the same as the method of pressure-relief unloading of a pressure chamber of the first embodiment. With reference to FIG. 18, similar to the first embodiment, the check valves 43 are selectively mounted between the two side openings 37, 25 and the corresponding signal chambers 1, 9. Therefore, the signal chambers 1, 9 may be instantly refilled with oil through the check valves 43.

Fourth Embodiment

With reference to FIGS. 19 to 21, a fourth embodiment of the hydraulic cushioning device has a signal generator X and a cushioning module Y. The cushioning module Y has a slide valve. The signal generator X is disposed in a first chamber 3 or a second chamber 8 of a cushioning cylinder Z, and controls movements of the first slide valve 12 via an oil line. By the methods of pressure-relief unloading of a pressure chamber and throttling backpressure of a return chamber, a moving velocity of a piston of the cushioning cylinder Z may be controlled, and a unidirectional cushioning effect may be achieved. With reference to FIG. 19, the first slide valve 12 and the signal generator X in the first chamber 3 are used for demonstration. FIG. 19 shows structural relationships between the first slide valve 12 and the first major hole 15 of the hydraulic system along with flowing directions of oil under a non-cushioning status.

Further, with reference to FIG. 20, the first valve 12 shown in FIG. 19 may be replaced with the valve core 12A.

Furthermore, with reference to FIG. 21, a check valve 43 may be mounted between the first outer opening 14 and the first signal chamber 1 of FIGS. 19 and 20, for oil to flow one-way to the first signal chamber 1 from the first outer opening 14. When the piston of the cushioning cylinder Z starts to move in a reverse direction, oil from the first outer opening 14 may surpass the damping hole 20 and flow rapidly to the first signal chamber 1 of the signal generator X through the check valve 43, in case that the oil is throttled by the damping hole 20 and is unable to fill the first signal chamber 1 in time.

Moreover, the substitution choices of the slide valves 12, 18 in the first embodiment as shown in FIG. 8 may also be applied to the fourth embodiment of the present invention. The aforementioned slide valve 12 and the valve core 12A may be assembled with the check valve 43 and be further adapted as a combined valve F. Besides preserving functions of the first slide valve 12, the combined valve F is also equipped with a function of the check valve 43 that may refill the first signal chamber 1 with oil rapidly. A check-valve rod of the combined valve F may be chosen from the first check-valve rod 21A, the second check-valve rod 21B, the third check-valve rod 21C, and the fourth check-valve rod 21D, the same as the first embodiment of the present invention.

Fifth Embodiment

With reference to FIGS. 22 to 26, a fifth embodiment of the hydraulic cushioning device has a signal generator X and a cushioning module Y. The cushioning module Y has a slide valve. The signal generator X is disposed in a first chamber 3 or a second chamber 8 of a cushioning cylinder Z, and controls movements of the first slide valve 12 via an oil line 35. By the method of throttling backpressure of a return chamber, a moving velocity of a piston of the cushioning cylinder Z may be controlled, and a unidirectional cushioning effect may be achieved. In FIGS. 22 to 26, the first signal chamber 1 disposed in the first chamber 3 is adopted for demonstration. The slide valve may be chosen from the first slide valve 12, the first valve core 12A, the second valve core 12B, and the third valve core 12C of the second embodiment. When the piston of the cushioning cylinder Z moves to an end of a stroke in the first chamber 3, a cushioning effect may be provided. Detailed description of working mechanism is the same as the second embodiment, and is thereof omitted.

Furthermore, with reference to FIG. 26, a check valve 43 may be mounted between the first outer opening 14 and the first signal chamber 1 in FIGS. 22 to 25, for oil to flow one-way to the first signal chamber 1 from the first outer opening 14. When the piston of the cushioning cylinder Z starts to move in a reverse direction, oil from the first outer opening 14 may surpass the damping hole 20 and flow rapidly to the first signal chamber 1 of the signal generator X through the check valve 43, in case that the oil is throttled by the damping hole 20 and is unable to fill the first signal chamber 1 in time. A larger negative pressure may occur if the oil fails to fill the first signal chamber 1 in time.

Moreover, the substitution choices of the slide valves 12, 18 in the first embodiment as shown in FIG. 8 may also be applied to the fifth embodiment of the present invention. The aforementioned slide valve 12 and the valve core 12A may be assembled with the check valve 43 and be further adapted as a combined valve F. Besides preserving functions of the first slide valve 12, the combined valve F is also equipped with a function of the check valve 43 that may refill the first signal chamber 1 with oil rapidly. A check-valve rod of the combined valve F may be chosen from the first check-valve rod 21A, the second check-valve rod 21B, the third check-valve rod 21C, and the fourth check-valve rod 21D, the same as the first embodiment.

With reference to FIGS. 1 to 26, a cushioning cylinder Z has a cylinder body 2, a piston rod 4, a piston 6, a top end B, and a bottom end A. The piston 6 and the piston rod 4 are connected as a piston assembly sliding in the cylinder body 2, and the piston 6 divides the space inside the cylinder body 2 into a first chamber 3 and a second chamber 8. The cushioning cylinder Z may be connected with any of the abovementioned hydraulic cushioning devices via oil lines. The cushioning module Y of the hydraulic cushioning device is formed integrally on or assembled to the cushioning cylinder Z. The signal generators X are disposed in the two chambers 3, 8 of the cushioning cylinder Z, are able to control slide valves of the cushioning module Y with oil at an end of a stroke, and further adjust hydraulic pressure in a pressure chamber or a return chamber of the cushioning cylinder Z. By pressure-relief unloading of the pressure chamber and/or the throttling backpressure of the return chamber, the signal generators X are able to control the velocity of the piston 6 and generate a cushioning effect to the cushioning cylinder Z. Detailed mechanism has been described in the foregoing paragraphs.

Besides, the cushioning module Y of the hydraulic cushioning device is formed integrally on or assembled to the top end B or the bottom end A. Axes of the holes of the cushioning module Y are disposed perpendicularly or parallelly on the same plane with an axis of the cushioning cylinder Z. For the cushioning module Y having two sets of holes, the axes are parallelly arranged, and the major holes and the minor holes of the two sets of the holes are disposed in perpendicular directions. As a result, the major oil groove of one of the two major holes aligns with the minor oil groove of the other one of the two major holes, perpendicular to the axes of the holes.

Moreover, the cushioning module Y of the hydraulic cushioning device is formed integrally on or assembled to the top end B or the bottom end A. The axes of the holes of the cushioning module Y are arranged in a parallel direction, and are perpendicular to the axis of the cushioning cylinder Z on the same plane.

Furthermore, the two slide valves of the cushioning module Y may be formed integrally on or assembled to the top end B and the bottom end A respectively via oil lines. Two axes of the two slide valves are perpendicular or parallel to the axis of the cushioning cylinder Z, and are located on the same plane.

Additionally, the two slide valves of the cushioning module Y may be separated into two portions, wherein each one of the two portions has a respective one of the two slide valves and is formed integrally on or assembled to the top end B or the bottom end of the cushioning cylinder Z via oil lines. The two axes of the two slide valves are perpendicular or parallel to the axis of the cushioning cylinder Z, and are located on the same plane.

The aforementioned descriptions are based on the cushioning cylinder Z with only one piston rod. If the cushioning cylinder Z is equipped with two piston rods, a chamber inside the cushioning cylinder Z is similar to the first chamber 3. Also, the mechanism is the same as the cushioning cylinder Z with only one piston rod, so detailed description thereof will not be repeated.

With reference to FIGS. 1 to 26, more embodiments depending on practical requirements may be easily modified from the five embodiments of the present invention. 

1. A hydraulic buffer connected with a cylinder that is controlled and buffered by the hydraulic buffer, with the hydraulic buffer comprising: at least one signal generator disposed in a chamber of the cylinder and having: a signal chamber disposed on a top end or a bottom end of the cylinder; and a signal plug slidable relative to the signal chamber and protruding on a side of a piston assembly of the cylinder; and a buffering module integrally formed on or assembled to the cylinder and having: a valve body; at least one slide valve each respectively connected to the at least one signal generator, controlled by the at least one signal generator to adjust a hydraulic flow passing into and out of the cylinder, and having a damping hole disposed therethrough; and at least one elastic component mounted in the valve body and abutting the valve body and the at least one slide valve; wherein the signal plug moving with the piston assembly selectively enters and slides in the signal chamber, with the signal chamber independent from the chamber of the cylinder, oil may is thereby sent from the signal chamber with part of the oil flowing through the damping hole, and a rest of the oil that is sent from the signal chamber pushing the at least one slide valve to move against the at least one elastic component, and with the hydraulic flow passing into and out of the cylinder adjusted and buffered by at least one of the methods of pressure-relief unloading of a pressure chamber and throttling backpressure of a return chamber.
 2. The hydraulic buffer as claimed in claim 1, wherein the hydraulic buffer further has at least one check valve or at least one combined valve equipped with functions of the at least one check valve, with the signal chamber refilled with oil through the at least one check valve or the at least one combined valve.
 3. A cylinder comprising: a cylinder body having a top end and a bottom end; a piston assembly slidably moveable in the cylinder body and having: a piston rod; and a piston mounted with the piston rod and dividing a space inside the cylinder body into a first chamber and a second chamber; a hydraulic buffer comprising: at least one signal generator disposed in one of the first chamber and the second chamber and having: a signal chamber disposed on the top end or the bottom end of the cylinder body; and a signal plug slideable relative to the signal chamber and protruding on a side of the piston assembly; and a buffering module integrally formed on or assembled to the cylinder body and having: a valve body; at least one slide valve each respectively connected to the at least one signal generator, controlled by the at least one signal generator to buffer the piston by at least one of methods of pressure-relief unloading of a pressure chamber and throttling backpressure of a return chamber and to adjust a hydraulic flow passing into and out of the cylinder chamber, and having a damping hole disposed therethrough; and at least one elastic component mounted in the valve body and abutting the valve body and the at least one slide valve; wherein the signal plug moving with the piston assembly selectively enters and slides in the signal chamber, wherein the signal chamber is independent from the first chamber or the second chamber, wherein oil is sent from the signal chamber with part of the oil flowing through the damping hole and the rest of the oil that is sent from the signal chamber pushing the at least one slide valve to move against the at least one elastic component, and wherein the oil passing into and out of the signal chamber is adjusted and buffered by the at least one of the methods of pressure-relief unloading of the pressure chamber and throttling backpressure of the return chamber.
 4. The cylinder as claimed in claim 3, wherein the buffering module has two slide valves, and wherein the two slide valves are respectively integrally formed on or assembled to the bottom end or the top end of the cylinder.
 5. The cylinder as claimed in claim 3, wherein the signal plug is integrally formed on the piston assembly, or is manufactured from a wear-resistant or elastic material and is mounted to the piston assembly.
 6. The cylinder as claimed in claim 4, wherein the signal plug is integrally formed on the piston assembly, or is manufactured from a wear-resistant or elastic material and is mounted to the piston assembly.
 7. The cylinder as claimed in claim 3, wherein the hydraulic buffer further has at least one check valve or at least one combined valve equipped with functions of the at least one check valve, with the signal chamber refilled with oil through the at least one check valve or the at least one combined valve.
 8. The cylinder as claimed in claim 7, wherein the buffering module has two slide valves, and wherein the two slide valves are respectively integrally formed on or assembled to the bottom end or the top end of the cylinder.
 9. The cylinder as claimed in claim 7, wherein the signal plug is integrally formed on the piston assembly, or is manufactured from a wear-resistant or elastic material and is mounted to the piston assembly.
 10. The cylinder as claimed in claim 8, wherein the signal plug is integrally formed on the piston assembly, or is manufactured from a wear-resistant or elastic material and is mounted to the piston assembly. 